CPT test methods are governed by ASTM standard D-3441 "Standard Test Method for Deep, Quasi-Static, Cone and Friction-Cone Penetration Tests of Soil." CPT is a geotechnical technique for determining soil strength parameters of near surface soils to depths of approximately 300 ft. CPT uses hydraulically operated rams mounted on a specially designed truck to push various measurement probes into the soil. One meter long threaded, hollow steel pipe sections are used to incrementally lengthen the pushing stem. Electrical cables attached to the measurement probes are threaded through the hollow pipes and connected to electronic data acquisition and analysis equipment in the truck.
During the penetration process the forces required to advance the probe are recorded on the data acquisition system. This provides a continuous record of the soil parameters during the testing process.
Numerous instruments are used to detect groundwater contamination, such as turbidity, chemical concentration, fluorescence and pH. Typically, the pH measurements are performed by obtaining a sample from a monitoring well and conducting the test on the obtained sample in the laboratory.
Some applications of CPT and bore hole sampling are as follows:
U.S. Pat. No. 5,246,862 to Grey et al. discloses a penetrometer having a reagent carrying tape for detecting contaminants in soil while the penetrometer is driven into the ground. The tape is pressed against an optical window. Contaminants in the soil reacting with the reagent cause an optically sensible reaction in the tape to occur. Changes in the chemical character of the tape are determined and recorded.
U.S. Pat. No. 5,128,882 to Cooper et al. discloses a method and apparatus for real time, on-site detection and analysis of contaminant in soil. The apparatus continuously measures and records specific spectral properties of potentially contaminated soil along a typically vertical profile as a soil penetrating probe penetrates the soil. The probe is fitted with a light transparent window and a light source disposed internally of the probe. Light from internally of the probe passes through the window and is reflected back through the window from the soil as the probe passes through the soil. The light reflected from the soil back through the window is collected by a fiber optic link within the probe. The collected light is then transmitted through the fiber optic link to the surface for measurement and recordation of spectral distribution and intensity. The apparatus allows rapid on-site determination of location, depth, and quantity of contaminant in soils.
U.S. Pat. No. 4,535,843 to Jageler discloses an apparatus operable on a wireline logging cable for sampling and testing fluids in a bore hole and transmitting the results obtained from such testing to the surface. The apparatus includes a chamber having a three electrode system for measuring acidity (pH) and redox potential (Eh). At spaced intervals along the bore hole, a sample of fluid is drawn into the apparatus and tested. Conventional electrical circuits are used to send appropriate signals through a wireline to the surface where the ph and Eh of the formation fluid can be displayed or read out.
U.S. Pat. No. 3,518,530 to Wilson discloses a device for determining an electrochemical factor as the device is lowered into a hole. The electrochemical factor is recorded in relationship to another function, such as depth.
U.S. Pat. No. 2,922,103 to Smith discloses a device for measuring the electrical resistivity of well bore fluids while the device is being lowered through the well bore.
U.S. Pat. No. 2,838,730 to Lebourg discloses a device having electrodes for determining the resistivity of the mud in a bore hole.